The present invention relates to staplers, and more particularly to jam clearing mechanisms for staplers.
Heavy duty staplers typically include a base, a cartridge assembly pivotally mounted to the base, and a lever assembly including a lever arm 16 that will provide a force to the cartridge assembly to drive a staple through a stack of sheets.
Cartridge assemblies commonly include a cartridge housing and a magazine positioned in the cartridge housing and designed to feed staples for the stapling process. The magazine typically includes a magazine housing and a rail positioned in the magazine housing to support a row of staples in preparation for the stapling process. The rail is commonly spaced from the front wall of the magazine housing to provide an exit space for a staple to be driven down through an opening in the magazine housing and into a stack of sheets.
For a variety of reasons, staplers sometimes become jammed. While there are many different modes of jamming, one common mode is for a misformed staple to become wedged in the exit space between the rail and the front wall of the magazine housing. This situation usually requires the user to turn the stapler over and remove the jammed staple by inserting a thin implement into the opening and prying the jammed staple out. It can be appreciated that it would be desirable to have a stapler that can remove jammed staples without the need to turn the stapler over and manually pry it out of the opening.
The present invention provides a stapler that facilitates removal of jammed staple by merely actuating a retractor that retracts the rail. This widens the exit space between the front edge of the rail and the front wall of the magazine housing, thus allowing the jammed staple to fall out of the magazine via gravity.
More specifically, the present invention provides a stapler comprising a base, and a cartridge assembly coupled to the base. The cartridge assembly includes a magazine having a magazine housing with a dispensing opening and a rail positioned in the magazine housing. The rail is movable relative to the housing between a static position toward the opening and a retracted position away from the opening. A rail retractor is adapted to engage the rail and move the rail from the static position to the retracted position to facilitate removal of a jammed staple.
In one embodiment, the retractor is designed to engage a tab on the rail. In order to allow the magazine to be removed from the cartridge housing for loading staples, the retractor is preferably designed so that it will not interfere with the longitudinal movement of the magazine (including the tab on the rail). For example, the retractor can be designed so that in an engaged position the retractor engages the tab and is at least partially aligned with the tab in a direction parallel to the longitudinal axis, and in a disengaged position the retractor is disengaged with the tab and is not aligned with the tab to facilitate movement of the magazine out of the housing for staple loading.
The retractor can be embodied in many different designs. In one embodiment, the retractor is rotatable and includes a handle, a rotatable shaft coupled to the handle, and an actuator coupled to the shaft. The handle is easily accessible by the user without the need to turn the stapler over.
The present invention is also embodied in a method of removing a staple jammed in a stapler. The method includes increasing the exit space between the rail and the front wall of the magazine housing. This method can be readily performed using the apparatus (e.g., retractor) described above.